Administration Of Infiltration Anaesthetic Into The Perineum
Procedure
- Decide where the episiotomy will be made. If the care provider is standing to the right of the woman, a mediolateral episiotomy will usually be made from the middle of the posterior commissure, in the direction of the left ischial tuberosity (from the median line with an angle of about 45° past the anus).
- Put on the sterile gloves.
- Draw 10-20 ml local anaesthetic into a syringe; place a long needle on the syringe.
- Place two fingers between the head of the foetus and the posterior commissure and stretch the perineum.
- Disinfect the injection and episiotomy site with a gauze soaked in a 1% chlorhexidine solution or a 10% povidone-iodine (Betadine®) solution.
- Insert the needle into the perineum as close as possible under the skin via the posterior commissure. The needle should follow the route of the planned episiotomy.
- Check that the point of the needle has not inadvertently entered a blood vessel by aspirating the hypodermic syringe slightly; if it is located intravascularly, withdraw the needle a little and check again.
- As the needle is gradually drawn back, inject half the anaesthetic under the skin.
- Repeat this procedure several times in a fan-shaped direction around the point of insertion in the posterior commissure.
Local anaesthetics are potentially dangerous substances. The therapeutic spectrum, the range between effective and toxic concentration, is fairly narrow. If a practitioner is unaware that an anaesthetic requires 3 to 5 minutes before it takes effect, they may inject increasingly more anaesthetic, which may lead to toxic concentrations of the anaesthetic. Overdose symptoms are dependent on the rate at which the concentration of the anaesthetic rises in the blood. The following symptoms can occur due to resorption from the tissues:
- Anxiety.
- Transpiration.
- Confusion.
- Numb feeling in tongue and lips.
- Impaired speech.
- Visual and auditory disorders.
- Twitching in the face.
If the medication accidentally enters a vein directly then the following symptoms can occur:
- Tremors.
- Muscle cramps.
- Convulsions.
- Apnoea.
- Cardiac arrest.
These symptoms arise from the effects of the drug. The anaesthetic numbs the nerve and in this manner, deregulates the organ systems in which the nerve impulse is involved (cardiovascular, CNS).
Management in case of signs of overdose:
- Stop infiltration.
- Keep talking to the woman.
- In the event of a home birth, call for an ambulance immediately.
- If necessary, administer oxygen and insert an oropharyngeal airway (Mayo tube).
- If necessary, administer diazepam, ephedrine or atropine.
- If necessary, reanimate.